Department of Biotechnology, Research Institute (RIBHS) and College of Biomedical and Health Science, Konkuk University, Chungju, Chungbuk, 27478, South Korea.
Department of Physiology, Ajou University School of Medicine, Suwon, Gyeonggi, 16499, South Korea.
Appl Microbiol Biotechnol. 2016 Dec;100(24):10521-10529. doi: 10.1007/s00253-016-7717-z. Epub 2016 Jul 28.
Fragment engineering of monoclonal antibodies (mAbs) has emerged as an excellent paradigm to develop highly efficient therapeutic and/or diagnostic agents. Engineered mAb fragments can be economically produced in bacterial systems using recombinant DNA technologies. In this work, we established recombinant production in Escherichia coli for monovalent antigen-binding fragment (Fab) adopted from a clinically used anticancer mAB drug cetuximab targeting epidermal growth factor receptor (EGFR). Recombinant DNA constructs were designed to express both polypeptide chains comprising Fab in a single vector and to secrete them to bacterial periplasmic space for efficient folding. Particularly, a C-terminal engineering to confer an interchain disulfide bond appeared to be able to enhance its heterodimeric integrity and EGFR-binding activity. Conformational relevance of the purified final product was validated by mass spectrometry and crystal structure at 1.9 Å resolution. Finally, our recombinant cetuximab-Fab was found to have strong binding affinity to EGFR overexpressed in human squamous carcinoma model (A431) cells. Its binding ability was comparable to that of cetuximab. Its EGFR-binding affinity was estimated at approximately 0.7 nM of Kd in vitro, which was quite stronger than the binding affinity of natural ligand EGF. Hence, the results validate that our construction could serve as an efficient platform to produce a recombinant cetuximab-Fab with a retained antigen-binding functionality.
单克隆抗体 (mAb) 的片段工程已成为开发高效治疗和/或诊断试剂的极佳范例。采用重组 DNA 技术,可以在细菌系统中经济地生产工程化的 mAb 片段。在这项工作中,我们建立了从临床使用的针对表皮生长因子受体 (EGFR) 的抗癌 mAB 药物西妥昔单抗中获得的单价抗原结合片段 (Fab) 在大肠杆菌中的重组生产。设计了重组 DNA 构建体,以便在单个载体中表达组成 Fab 的两条多肽链,并将它们分泌到细菌周质空间以进行有效的折叠。特别是,赋予链间二硫键的 C 末端工程似乎能够增强其异二聚体完整性和 EGFR 结合活性。通过质谱法和晶体结构(分辨率为 1.9 Å)验证了纯化最终产物的构象相关性。最后,我们发现重组西妥昔单抗-Fab 与人鳞状细胞癌模型 (A431) 细胞中过表达的 EGFR 具有很强的结合亲和力。它的结合能力与西妥昔单抗相当。其 EGFR 结合亲和力在体外约为 0.7 nM 的 Kd,这比天然配体 EGF 的结合亲和力要强得多。因此,这些结果验证了我们的构建可以作为生产保留抗原结合功能的重组西妥昔单抗-Fab 的有效平台。